1. Field of the Invention
This invention relates to single crystals and more specifically to single, doped beryllium lanthanate crystals and to the use of such crystals as laser hosts.
2. Description of the Prior Art
The use of lasers in science and industry has received wide acceptance in an ever increasing variety of applications. Lasers have found use in such diverse areas as range finding apparatus, optical surgery and metal drilling. Briefly, lasers operate on the principle of light amplification through stimulated emission of radiation and can create extremely intense concentrations of light. The light beam produced in the laser cavity is amplified in a laser host material. Materials which have been used as laser hosts include gases, liquids, glasses and single crystalline solids.
When single crystalline solids are utilized as laser hosts the crystals are generally in the form of elongated rods. The structure of the crystalline material must be very nearly perfect since any optical inhomogeneities will cause distortion and scattering of the laser beam and thereby reduce the intensity and coherence of the radiation. Imperfections in the crystal which adversely affect lasing performance include misorientations, chemical concentration gradients, dislocations, inclusions and bubbles.
Material of potential or realized commercial importance as rare-earth ion laser hosts include Y.sub.3 Al.sub.5 O.sub.2 :Nd (YAG:Nd) and Y.sub.2 Al.sub.2 O.sub.6 :Nd (YALO) as well as the fluoroapatite (FAP) and silicate oxyapatite (SOAP) based materials and some variations of these. YAG:Nd has so far realized the largest commercial application among these materials because of its favorable combination of spectroscopic, thermal transport and stress-optic properties. It is, however, difficult and expensive to grow, especially at high doping levels.